Horticulturists have been researching potatoes for decades. One of the mysteries many have tackled is the effect of leaving flowers on potato plants. What are the pros and are there any cons?
Looking at the body of evidence provided by horticulturists, it’s a good idea to remove any flowers that grow on potato plants. But it’s not essential because it’s unlikely to affect your plant growth or potato yield negatively. On the other hand, if the flowers develop fruit, it’s best to remove them because the fruit is toxic.
Does potato have flowers?
Some potato varieties have flowers, while others don’t. However, in a paper on Potato Propagation published by North Dakota State University, Carina De Luca states that “most potato cultivars produce fruit.”
It, therefore, stands to reason that most potatoes have flowers at one time or another. If and when they do, they grow on the stems of the potato that sprout from the eye of the potato tuber that we ultimately eat.
When we grow potatoes, we plant what is known as seed potatoes. This is a section of a potato tuber that has a growing “eye” or a little green shoot.
Of course, you plant seed potatoes by digging them into the ground. The stems continue to grow from the potato eyes and eventually form vines covered with green potato leaves.
Often the potato plant will flower and sometimes it will also produce fruit. Fruit is less common than flowers.
What does potato fruit look like?
Potato fruit looks very much like green cherry tomatoes. This isn’t very surprising since, like tomatoes, potatoes belong to the Solaneous or nightshade family. So, too, do peppers and eggplants.
This is probably a good time to point out that potatoes and tomatoes often share diseases. For example, late blight, the disease that resulted in the Irish potato famine in the 1840s, also affects tomatoes.
So, you can grow these different nightshade family plants together, but they aren’t going to protect one another.
If you’re looking for good companion plants to grow with your potatoes, mealies, peas, beans, marigolds, and strawberries are all a good bet. They will protect your underground crop.
Is it okay to leave potato flowers?
There is some disagreement about the answer to the question. While most sources recommend that you remove potato flowers, there is no hard and fast rule.
Often the flowers will shrivel up and fall off without you doing anything. But if the flowers thrive, they are likely to produce fruit.
Gretchen Voyle, writing under the banner of Michigan State University’s Extension, says the flowers usually fall off the potato plant in the hot dry months of July and August. When the weather is unseasonably cool they are less likely to fall off and, therefore, more likely to turn into fruit.
So, if the weather is cool at the end of the growing season, or the flowers start to form, then it’s best to remove the flowers. The problem is that they contain high volumes of solanine which is toxic and can make people and animals very sick.
Solanine is the same substance found in potatoes that are left in the sun after harvesting. You can identify the solanine by the green tinge the skin gets.
This means you can’t eat the fruit. But should you leave potato flowers so that you can harvest the seeds of the fruit?
Voyle says, don’t bother. First of all, you’re not going to produce the same kind of potatoes from the seeds of its fruit. Secondly, it’ll take years to grow a potato from the seed of its fruit.
Some growers and potato breeders do save the seeds of potato fruit. But they are scientists who are doing this in an endeavor to produce new potato varieties. Not home growers like you or me.
When Does a Potato Plant Flower?
Potato flowers appear at the end of the growing season in some areas. But according to the Oregon State University Extension Service, in their part of the world, the flowers that potato plants produce show up nearer to the middle of the growing season.
They also point out that potato flowers don’t produce nectar.
Is There a Benefit of Removing Potato Flowers?
If removing potato flowers increases the yield of your crop it might be worth the effort. But there are mixed results.
In any case, there’s certainly no harm in removing the flowers.
An early research project was undertaken by horticulturist W.L. Bartholdi at the University of Minnesota”s Agricultural Experiment Station in 1942. The results are published in a technical bulletin, Influence of Flowering and Fruiting Upon Vegetative Growth and Tuber Yield in the Potato.
His experiments found that potato plants that fruited yielded a lower weight of potatoes – as much as 12.77-27.24% lower. Where the flowers were removed from the potato plant, the yield was highest.
A paper published in the Canadian Journal of Plant Science in 1990 presents mixed results.
For instance, studies at irrigated and dryland sites for cloning potatoes showed that removing potato flowers increased yields significantly. However, at another location, when potatoes were planted in dryland conditions, it didn’t increase the yield significantly.
Because of this, their conclusion was that the effect of flower removal on the yield of potato tubers is largely dependent on environmental conditions.
The paper is titled The Effect of Flower Removal on Potato Tuber Yield and was written by S.H. Jansky and D.M. Thompson who were working for the Department of Horticulture and Forestry at North Dakota State University.
What Do Potato Plant Flowers Look Like?
Potato plant flowers look a lot like tomato flowers in terms of form and size. However, potato flowers may be pink, white, or lavender in color, depending on the variety.
If you are going to remove the flowers, all you have to do is pinch them off.
Do Potato Flowers Always Bloom?
If your potato plants flower, the flowers will usually bloom (open up).
Our tip is to remove any flower potato plants produce. It’s not likely to result in a lower yield of potatoes, and if the potato plant produces its toxic fruit, this comes with its own risks.